You could have a broken spring. Garage door springs are very dangerous do not attempt to fix it yourself. Contact Everything Doors & More at 262-456-7667 for repairs.
You could have a slipped or broken cable. Do not attempt to operate the door with a broken or slipped cable because you damage the door further or cause the door to completely fall out of the tracks. Contact Everything Doors & More at 262-456-7667 for repairs.
The safety sensor could be blocked, misaligned or damaged. If the photo sensors are out of alignment the door opener will generally flash indicating a problem with the photo eyes.
There may have been a lightning strike in the area the knocked out the logic board in the garage door opener.